As the world transitions to a low-carbon energy future, near-term, large-scale deployment of solar power will be critical to mitigating climate change by midcentury. Climate scientists estimate that the world will need 10 terawatts (TW) or more of solar power by 2030—at least 50 times the level deployed today. At the MIT Photovoltaics Research Laboratory (PVLab), teams are working both to define what’s needed to get there and to help make it happen. “Our job is to figure out how to reach a minimum of 10 TW in an economically and environmentally sustainable way through technology innovation,” says Tonio Buonassisi, associate professor of mechanical engineering and lab director.

Their analyses outline a daunting challenge. First they calculated the growth rate of solar required to achieve 10 TW by 2030 and the minimum sustainable price that would elicit that growth without help from subsidies. Current technology is clearly not up to the task. “It would take between $1 trillion and $4 trillion of additional debt to just push current technology into the marketplace to do the job, and that’d be hard,” says Buonassisi. So what needs to change?

Using models that combine technological and economic variables, the researchers determined that three changes are required: reduce the cost of modules by 50 percent, increase the conversion efficiency of modules (the fraction of solar energy they convert into electricity) by 50 percent, and decrease the cost of building new factories by 70 percent. Getting all of that to happen quickly enough—within five years—will require near-term policies to incentivize deployment plus a major push on technological innovation to reduce costs so that government support can decrease over time.